The present disclosure relates to a sewing machine in which a magnitude of a gap between a sewing needle and a hook point of a shuttle can be adjusted.
In related art, a sewing machine is mainly provided with a bed portion, a pillar, an arm portion and a head portion. The arm portion includes a drive shaft that is driven by a sewing machine motor. The head portion includes a needle bar base that supports a needle bar. Due to the rotation of the drive shaft, the needle bar moves in the up-down direction. The bed portion includes a shuttle that rotates in accordance with a rotation of a lower shaft that moves in connection with the drive shaft. Due to the concerted movement of the needle bar and the shuttle, an upper thread that is supplied to a sewing needle attached to the needle bar is interlaced with a lower thread that is supplied from a bobbin housed in the shuttle, thus forming a stitch on a work cloth.
In a sewing machine, in order to reliably form stitches, adjustment of a magnitude of a gap between a sewing needle and a hook point of the shuttle is important. Thus, the sewing machine includes a mechanism that can adjust the gap between the sewing needle and the hook point of the shuttle. Hereinafter, the gap between the sewing needle and the hook point of the shuttle is referred to as a needle gap. For example, a sewing machine is known that is provided with a needle bar base that supports a needle bar, a holding shaft and two clips. The holding shaft is inserted into a hole in the upper portion of the needle bar base, and rotatably supports the needle bar base. The two clips are attached to the holding shaft such that the two clips clamp the upper portion of the needle bar base. The two clips regulate the movement of the needle bar base in the axial direction of the holding shaft. The holding shaft is inserted into a hole that is formed in a sewing machine arm, and is fixed inside the hole by a screw. In the sewing machine, the adjustment of the needle gap is performed by loosening the screw and causing the holding shaft to move slightly in the axial direction.